Due to what looks like a rebasing error, this patch doesn't compile.
I haven't read the code yet.
Ethan
On Wed, Apr 11, 2012 at 17:15, Ben Pfaff <b...@nicira.com> wrote:
> The existing functions for reading and writing the values of subfields only
> handle subfields up to 64 bits wide. These new functions handle subfields
> of any width.
>
> Signed-off-by: Ben Pfaff <b...@nicira.com>
> ---
> lib/meta-flow.c | 41 ++++++++++++++++++++++++++++++++++++-----
> lib/meta-flow.h | 20 ++++++++++++++++++++
> 2 files changed, 56 insertions(+), 5 deletions(-)
>
> diff --git a/lib/meta-flow.c b/lib/meta-flow.c
> index 11d27b1..a8cfd74 100644
> --- a/lib/meta-flow.c
> +++ b/lib/meta-flow.c
> @@ -2241,12 +2241,27 @@ mf_format(const struct mf_field *mf,
> }
> }
>
> -/* Makes a subfield starting at bit offset 'ofs' and continuing for 'n_bits'
> in
> - * 'rule''s field 'mf' exactly match the 'n_bits' least-significant bits of
> - * 'x'.
> +/* Makes subfield 'sf' within 'rule' exactly match the 'sf->n_bits'
> + * least-significant bits in 'x'.
> *
> - * Example: suppose that 'mf' is originally the following 2-byte field in
> - * 'rule':
> + * See mf_set_subfield() for an example.
> + *
> + * The difference between this function and mf_set_subfield() is that the
> + * latter function can only handle subfields up to 64 bits wide, whereas this
> + * one handles the general case. On the other hand, mf_set_subfield() is
> + * arguably easier to use. */
> +void
> +mf_write_subfield(const struct mf_subfield *sf, const union mf_subvalue *x,
> + struct cls_rule *rule)
> +{
> + const struct mf_field *field = sf->field;
> + union mf_value value, mask;
> +
> + mf_get(field, rule, &value, &mask);
> + bitwise_copy(x, sizeof *x, 0, &value, field->n_bytes, sf->ofs,
> sf->n_bits);
> + bitwise_one ( &mask, field->n_bytes, sf->ofs,
> sf->n_bits);
> + mf_set(field, &value, &mask, rule);
> +}
> *
> * value == 0xe00a == 2#1110000000001010
> * mask == 0xfc3f == 2#1111110000111111
> @@ -2314,6 +2329,22 @@ mf_set_subfield_value(const struct mf_subfield *sf,
> uint64_t x,
> }
> }
>
> +/* Initializes 'x' to the value of 'sf' within 'flow'. 'sf' must be valid
> for
> + * reading 'flow', e.g. as checked by mf_check_src(). */
> +void
> +mf_read_subfield(const struct mf_subfield *sf, const struct flow *flow,
> + union mf_subvalue *x)
> +{
> + union mf_value value;
> +
> + mf_get_value(sf->field, flow, &value);
> +
> + memset(x, 0, sizeof *x);
> + bitwise_copy(&value, sf->field->n_bytes, sf->ofs,
> + x, sizeof *x, 0,
> + sf->n_bits);
> +}
> +
> /* Returns the value of 'sf' within 'flow'. 'sf' must be valid for reading
> * 'flow', e.g. as checked by mf_check_src() and sf->n_bits must be 64 or
> * less. */
> diff --git a/lib/meta-flow.h b/lib/meta-flow.h
> index e062312..91d52c7 100644
> --- a/lib/meta-flow.h
> +++ b/lib/meta-flow.h
> @@ -207,6 +207,7 @@ union mf_value {
> uint8_t mac[ETH_ADDR_LEN];
> struct in6_addr ipv6;
> };
> +BUILD_ASSERT_DECL(sizeof(union mf_value) == 16);
>
> /* Part of a field. */
> struct mf_subfield {
> @@ -215,6 +216,19 @@ struct mf_subfield {
> unsigned int n_bits; /* Number of bits. */
> };
>
> +/* Data for some part of an mf_field.
> + *
> + * The data is stored "right-justified". For example, if "union mf_subvalue
> + * value" contains NXM_OF_VLAN_TCI[0..11], then one could access the
> + * corresponding data in value.be16[7] as the bits in the mask htons(0xfff).
> */
> +union mf_subvalue {
> + uint8_t u8[16];
> + ovs_be16 be16[8];
> + ovs_be32 be32[4];
> + ovs_be64 be64[2];
> +};
> +BUILD_ASSERT_DECL(sizeof(union mf_value) == sizeof (union mf_subvalue));
> +
> /* Finding mf_fields. */
> const struct mf_field *mf_from_id(enum mf_field_id);
> const struct mf_field *mf_from_name(const char *name);
> @@ -253,12 +267,18 @@ void mf_set_wild(const struct mf_field *, struct
> cls_rule *);
> void mf_random_value(const struct mf_field *, union mf_value *value);
>
> /* Subfields. */
> +void mf_write_subfield(const struct mf_subfield *, const union mf_subvalue *,
> + struct cls_rule *);
> void mf_set_subfield(const struct mf_subfield *, uint64_t value,
> struct cls_rule *);
> void mf_set_subfield_value(const struct mf_subfield *, uint64_t value,
> struct flow *);
> +
> +void mf_read_subfield(const struct mf_subfield *, const struct flow *,
> + union mf_subvalue *);
> uint64_t mf_get_subfield(const struct mf_subfield *, const struct flow *);
>
> +
> void mf_format_subfield(const struct mf_subfield *, struct ds *);
> char *mf_parse_subfield__(struct mf_subfield *sf, const char **s);
> const char *mf_parse_subfield(struct mf_subfield *, const char *);
> --
> 1.7.2.5
>
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